As wireless communication networks continue to evolve, the number of users continues to grow dramatically. Such growth of users has required service providers to expand their networks and provide greater capacity to accommodate the additional users. One way that service providers have increased capacity is by dividing the “cells” of a cellular communication networks, for example, into smaller cells or sectors. As the number of sectors increases, additional base stations are required.
Further, additional frequency has been allocated for service providers to provide wireless communication services. For example, additional spectrum has been allocated in the 2 GHz range in the United States, commonly referred to as personal communication services (PCS) spectrum. However, wireless communication networks operating in the PCS frequency spectrum, which is higher than the 800 MHz spectrum for conventional cellular service, generally require additional base stations to provide service at the higher frequency. That is, a greater number of base stations are required in a given geographic region to accommodate the same number of users as a conventional 800 MHz cellular system because the base stations must be positioned closer to one another. Accordingly, as wireless communication networks have continued to expand, the number of cell cites and base stations have also continued to expand.
Further, as wireless communication networks continue to expand and the number of base stations increases, the accessibility of base stations for routine maintenance and updating of information becomes more challenging. Modifying or altering software at base stations can be a time consuming and often a difficult task for an operator.
With an increasing number of users on a given wireless communication network, there is a greater chance for interference between users. Also, users are often faced with the problems associated with multi-path interference. Multi-path interference, generally from an unwanted reflected signal such as a signal reflected off a building, leads to a received signal which does not match in phase. When the waves of the multi-path signal are out of phase, reduction in signal strength can occur, which is commonly known as “rayleigh fading” or “fast fading.” Other problems associated with multi-path signals include phase cancellation, delay spread, co-channel interference, etc.
One way to overcome interference in a wireless communication network is to provide an adaptive antenna system. Adaptive antenna systems, such as switched beam or adaptive array antenna systems, greatly improve the signal-to-noise ratio compared to a conventional omni-directional antenna used in a wireless communication network. Although wireless communication devices typically employ conventional omni-directional antennas, wireless communication networks typically employ antenna systems having an arrays of antennas adapted to receive signals from a plurality of wireless communication devices. For example, sectorized antenna systems subdivide an area of a cellular communication network into sectors using directional antennas. Each sector is treated as a different cell, which greatly increases the reuse of a frequency channel and reduces interference in the cellular communication network.
Switched beam arrays, which are well known in the art, accommodate a finite number of fixed, predetermined patterns. That is, a switched beam array antenna system forms multiple fixed beams with heighten sensitivity in predetermined directions. These antenna systems typically detect signal strength and choose from one of several predetermined fixed beams as the mobile moves throughout the sector.
In contrast, adaptive array antenna systems accommodate an infinite number of patterns that are adjusted in real time. Adaptive array antenna systems use signal processing algorithms and take advantage of the ability to effectively locate and track various signals to dynamically minimize interference and maximize intended signal reception. In particular, adaptive array antenna systems use control systems that continuously refocus the transmit lobe of the array so that the user is centered in the beam.
Adaptive array antenna systems offer excellent performance, but at the cost of significant compute power. A control system for an adaptive antenna array system, even though it may be implemented in digital logic, must enable beam focusing across precise coordinates of the wireless communication device in the wireless communication network. The compute power requirements either constrain the capability of an antenna system to support multiple users, or more likely increase the cost and complexity of the system by significantly increasing the processing requirements.
Accordingly, there is a need for an improved method of controlling an antenna system of a wireless communication network.
There is also a need for an improved method of maintaining an adaptive antenna system of a wireless communication network from a remote location.
There is a further need for an improved wireless communication circuit and network for controlling an adaptive antenna.
Finally, there is a need for communication network having an adoptive antenna system which can be controlled remotely.